摘要 |
A DC voltage input through an input terminal is applied through an inductor, to a power supply circuit unit and an input voltage detecting circuit. The input voltage detecting circuit detects the input DC voltage and when it is detected that the input voltage value may possibly cause malfunction, a control circuit turns off a switch circuit based on the detection output, whereby power supply from the power supply circuit to a transmission circuit is stopped, and malfunction of the transmission circuit is prevented.
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